The large-caps struggled in April after British Prime Minister Theresa May called a snap general election which has boosted sterling to a seven-month high.

Coupled with uncertainty around Brexit negotiations, a stronger currency has weighed on the index's dollar-earning firms, which enjoyed an accounting boost after sterling's 11 percent plunge in the immediate aftermath of the Brexit vote.

However, Bank of America Merrill Lynch strategists said they saw the pound playing less of a role for UK equities in the next twelve months.

"Relying on FX is likely a red herring," they said, adding any rallies in the pound may not be sustained long-term as the currency adapts to softer economic fundamentals.

The UK's GDP reading for the first quarter came in weaker than expected earlier on Friday, as a rise in inflation hit consumer-facing businesses, with the economy slowing sharply.

On the day, bank earnings were in focus.

Barclays (BARC.L) fell 5.2 percent, its biggest one-day loss since the aftermath of Britain's referendum vote to leave the European Union last June.

While Barclays' first quarter profit more than doubled, a weak performance at its investment banking arm disappointed as the bank missed out on a bond trading boom which boosted revenues at its U.S. peers.

"Taking a bit of a longer-term view, Barclays is still in a state of recovery and is moving towards its goal of being a UK retail bank and a transatlantic corporate bank, but this particular quarter I think the results were a bit disappointing compared to what analysts were expecting," Laith Khalaf, senior analyst at Hargreaves Lansdown, said.

The Scottish bank gained 4.7 percent after it swung to its first quarterly profit since September 2015, beating average forecasts in a sign of progress in its turbulent turnaround.

"While the group continues to make progress at an underlying level, there remain a number of significant legacy issues that continue to overhang the investment case," said Shore Capital analyst Gary Greenwood.

Shares in Mediclinic (MDCM.L) dropped 4.4 percent, pulling back after a 17.5 percent jump in the previous session after Abu Dhabi cancelled a 20 percent co-payment requirement for treatment at private healthcare facilities.

Miners were among the top gainers, with Antofagasta (ANTO.L), Anglo American (AAL.L) and Randgold Resources (RRS.L) all up between 1.6 percent and 2.4 percent as the price of copper edged higher. [MET/L]